222 REV. J. MILNE CUERAN. 



this rock occurs as intrusive masses. When sliced for the 

 microscope in its general character it is found to be a compound 

 of felspar, augite and magnetite. The rock is not quite non- 

 crystalline, but if a detailed examination of the district were 

 made, it would be found, probably, merging into the non- 

 crystalline augite-plagioclase rocks of Carcoar. 



Slices 96 to 101 are all examples of various textures in this 

 rock. An inspection of the slices with the hand-lens is sufficient 

 to detect augite sections of characteristic outline, parallel or 

 nearly so, to the clinopinseoid. 



Slice 107. — Gabbro, Carcoar, New South Wales. Gabbro rocks 

 are very extensively exposed in the valley of Belebula, above 

 Carcoar. The rock is locally called granite. All the ingredients 

 are macroscopic, and in texture somewhat coarser than the 

 average granite. In terming this rock a gabbro, I follow 

 Professor Judd, who reserves the term "gabbro" for non- 

 crystalline basic rocks, which would be called diabases if they 

 contained a considerable proportion of unindividualized ground- 

 mass.* 



Slice 11 3. — McKillop's Paddock, near Carcoar. This is a 

 rock much resembling a felsite in macroscopic characters. When 

 sliced for the microscope it is found to be of clastic origin, but 

 there is no doubt that the fragments of which it is composed 

 were themselves felsitic. This rock is inter-bedded with Silurian 

 ;slate. 



Slice 118. — Diorite from between Forbes and Eugowra. This 

 rock consists of an intimate mixture of fibrous hornblende, felspar 

 and magnetite. As the slice is ground down, the rock shows a 

 beautiful sap-green colour by transmitted light. The green horn- 

 blendic material is dichroic. Veins of a secondary felspathic 

 material form seams through the rock ; one of these is seen on 

 the slice. 



* Professor Judd — On the Tertiary Gabbro of Ireland and Scotland- 

 Quart. Journ. Geol. Soc, Vol. xlii., p. 61. 



